In a pot, combine the evaporated and condensed milk, milled rice, glutinous rice, 7-Up and sugar.
Mix well. Boil for 3 minutes stirring continuously. Strain.
Transfer the boiled rice to a moderate heat and cook over stirring continuously.
Add the corn and buko and continue cooking until thick.
Pour into a 12-inch round wooden container, cover with cheesecloth (katsa) and steam for 40 minutes to an hour. Slice diagonally and serve.